Removing metal contamination from surfaces of a processing chamber

ABSTRACT

A method for cleaning surfaces of a substrate processing chamber includes a) supplying a first gas selected from a group consisting of silicon tetrachloride (SiCl4), carbon tetrachloride (CCl4), a hydrocarbon (CxHy where x and y are integers) and molecular chlorine (Cl2), boron trichloride (BCl3), and thionyl chloride (SOCl2); b) striking plasma in the substrate processing chamber to etch the surfaces of the substrate processing chamber; c) extinguishing the plasma and evacuating the substrate processing chamber; d) supplying a second gas including fluorine species; e) striking plasma in the substrate processing chamber to etch the surfaces of the substrate processing chamber; and f) extinguishing the plasma and evacuating the substrate processing chamber.

CROSS REFERENCE TO RELATED APPLICATIONS

The present disclosure is a Division of U.S. application Ser. No.17/278,750, filed Mar. 23, 2021, which claims the benefit of U.S.National Phase Application under 35 U.S.C. 371 of InternationalApplication No. PCT/US2019/054477, filed on Oct. 3, 2019, which claimsthe benefit of U.S. Provisional Patent Application No. 62/741,754, filedon Oct. 5, 2018. The entire disclosures of the above-identifiedapplications are hereby incorporated by reference in their entirety.

FIELD

The present disclosure relates to substrate processing systems and moreparticularly to systems and methods for removing metal contaminationfrom surfaces of a processing chamber.

BACKGROUND

The background description provided here is for the purpose of generallypresenting the context of the disclosure. Work of the presently namedinventors, to the extent it is described in this background section, aswell as aspects of the description that may not otherwise qualify asprior art at the time of filing, are neither expressly nor impliedlyadmitted as prior art against the present disclosure.

Substrate processing systems may be used to perform etching, deposition,and/or other treatment of substrates such as semiconductor wafers.During processing, a substrate is arranged on a substrate support in aprocessing chamber. One or more gases are introduced into the processingchamber by a gas delivery system. Plasma may be struck during processingto enhance chemical reactions within the processing chamber. An RF biasmay also be supplied to the substrate support to control ion energy.

For example, etching may be performed using inductively-coupled plasma(ICP) generated by inductive coils arranged outside of a processingchamber adjacent to a dielectric window. Process gas flowing inside theprocessing chamber is ignited to create plasma. RF bias power may alsobe supplied to an electrode in the substrate support.

During substrate treatment such as deposition or etching, residue may bedeposited on surfaces of the processing chamber such as chamber walls.The residue may cause defects during processing of the substrates.Cleaning may be performed to remove the residue.

SUMMARY

A method for cleaning surfaces of a substrate processing chamberincludes a) supplying a first gas selected from a group consisting ofsilicon tetrachloride (SiCl₄), carbon tetrachloride (CCl₄), ahydrocarbon (C_(x)H_(y) where x and y are integers) and molecularchlorine (Cl₂), boron trichloride (BCl₃), and thionyl chloride (SOCl₂);b) striking plasma in the substrate processing chamber to etch thesurfaces of the substrate processing chamber; c) extinguishing theplasma and evacuating the substrate processing chamber; d) supplying asecond gas including fluorine species; e) striking plasma in thesubstrate processing chamber to etch the surfaces of the substrateprocessing chamber; and f) extinguishing the plasma and evacuating thesubstrate processing chamber.

In other features, the method includes g) repeating a) to c) and d) tof) N times, where N is an integer greater than zero. The second gas isselected from a group consisting of nitrogen trifluoride (NF₃), sulfurhexafluoride (SF₆), and carbon tetrafluoride (CF₄). a) to g) areperformed without a substrate located on a substrate support in thesubstrate processing chamber.

In other features, the method includes pre-coating the surfaces of thesubstrate processing chamber with a material selected from a groupconsisting of silicon (Si) and silicon oxide (SiO_(x)) after g).

In other features, a) to c) are performed after d) to f) during each ofthe N times. a) to c) are performed before d) to f) during each of the Ntimes.

In other features, prior to performing a) to g), the method includespre-coating the surface of the substrate processing chamber with amaterial selected from a group consisting of silicon (Si) and siliconoxide (SiO_(x)); and performing a substrate treatment. In otherfeatures, the method includes, after g), pre-coating the surface of thesubstrate processing chamber with a material selected from a groupconsisting of silicon (Si) and silicon oxide (SiO_(x)); and performing asubstrate treatment.

In other features, the substrate treatment comprises etching. Thesubstrate includes tin (Sn).

In other features, the method includes controlling a first pressure inthe substrate processing chamber during b) within a first pressurerange; and controlling a second pressure in the substrate processingchamber during e) within a second pressure range. The first pressurerange is less than the second pressure range.

In other features, the first pressure range is from 1 to 30 mT and thesecond pressure range is from 30 to 150 mT.

A substrate processing system for treating substrates includes aprocessing chamber comprising chamber walls and a substrate support. Agas delivery system selectively delivers gases to the processingchamber. A plasma generator selectively generates plasma in theprocessing chamber. A controller is configured to control the gasdelivery system and the plasma generator to a) supply a first gasselected from a group consisting of silicon tetrachloride (SiCl₄),carbon tetrachloride (CCl₄), a hydrocarbon (C_(x)H_(y) where x and y areintegers) and molecular chlorine (Cl₂), boron trichloride (BCl₃), andthionyl chloride (SOCl₂); b) strike plasma in the substrate processingchamber to etch the surfaces of the substrate processing chamber; c)extinguish the plasma and evacuate the substrate processing chamber; d)supply a second gas including fluorine species; e) strike plasma in thesubstrate processing chamber to etch the surfaces of the substrateprocessing chamber; and f) extinguish the plasma and evacuate thesubstrate processing chamber.

In other features, the controller is further configured to g) repeat a)to c) and d) to f) N times, where N is an integer greater than zero. Thesecond gas is selected from a group consisting of nitrogen trifluoride(NF₃), sulfur hexafluoride (SF₆), and carbon tetrafluoride (CF₄). Thecontroller is configured to remove a substrate from the substratesupport prior to performing a) to g). The controller is configured topre-coat the surfaces of the substrate processing chamber with amaterial selected from a group consisting of silicon (Si) and siliconoxide (SiO_(x)) after g). The controller is configured to perform a) toc) after d) to f) during each of the N times. The controller isconfigured to perform a) to c) before d) to f) during each of the Ntimes.

In other features, the controller is configured to, prior to performinga) to g), pre-coat the surface of the substrate processing chamber witha material selected from a group consisting of silicon (Si) and siliconoxide (SiO_(x)); and perform a substrate treatment. After g), thecontroller is configured to pre-coat the surface of the substrateprocessing chamber with a material selected from a group consisting ofsilicon (Si) and silicon oxide (SiO_(x)); and perform a substratetreatment.

In other features, the substrate treatment comprises etching. Thesubstrate includes tin (Sn).

In other features, the controller is configured to control a firstpressure in the substrate processing chamber during b) to a firstpressure range; and control a second pressure in the substrateprocessing chamber during e) to a second pressure range. The firstpressure range is less than the second pressure range.

In other features, the first pressure range is from 1 to 30 mT and thesecond pressure range is from 30 to 150 mT.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description, the claims and the drawings. Thedetailed description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of thedisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a functional block diagram of an example of a substrateprocessing system that includes a cleaning system according to thepresent disclosure;

FIGS. 2A to 2D illustrate cleaning of surfaces of the substrateprocessing system according to the present disclosure;

FIGS. 3A to 3E illustrate another example of cleaning of surfaces of thesubstrate processing system according to the present disclosure; and

FIG. 4 is a flowchart of an example of a method for cleaning thesurfaces the substrate processing system according to the presentdisclosure.

In the drawings, reference numbers may be reused to identify similarand/or identical elements.

DETAILED DESCRIPTION

The present disclosure relates to systems and methods for cleaningsurfaces of a processing chamber such as chamber walls to reduce metalcross-contamination. The cleaning method described herein removes metalcontaminants such as Tin (Sn), aluminum (Al), yttrium (Y), iron (Fe),and/or other metals more effectively than traditional cleaning methods.The cleaning systems and methods according to the present disclosure canbe used to periodically reset the processing chamber to its originalclean state.

Metal contamination in the processing chamber may cause process shiftsuch as etch rate changes. Metal contamination may also cause defectsthat adversely affect device performance. Typical specifications requiremetal contamination in the processing chamber to be less than 5 e¹⁰/cm².Traditional chamber cleaning methods result in metal contaminationlevels of approximately 1e¹¹/cm² to 1e¹²/cm². The cleaning systems andmethods described herein can significantly reduce metal contamination toless than 5 e¹⁰/cm².

For example, surfaces of an inductively coupled plasma processingchamber are typically pre-coated with a layer such as silicon (Si) orsilicon oxide (SiO_(x)). After etching of substrates including Sn isperformed, tin oxide (SnO_(x)) etch by-product or residue is depositedon the surfaces of the processing chamber. Cleaning may include a firstplasma processing step with molecular chlorine (Cl₂) and a second plasmaprocessing step with nitrogen trifluoride (NF₃). However, this chemistryhas a very slow SnO_(x) etch rate due to non-volatile etch byproducts.In other words, Sn halides (SnF_(x), SnCl_(x), and SnBr_(x)) arenon-volatile. Even with relatively long etch periods up to 300 seconds,the contamination levels remain at or above 1e¹¹/cm² to 1e¹²/cm².

Another cleaning approach using molecular hydrogen (H₂) plasma etchs Snor SnO_(x) to form volatile tin hydride (SnH_(x)). However, SnH_(x) isnot stable at high temperatures and tends to dissociate back to metallicSn and re-deposit on the surfaces in the processing chamber.

Systems and methods according to the present disclosure are used toclean surfaces in the processing chamber to reduce metal contamination.In some examples, the surfaces of the processing chamber are pre-coatedwith a layer such as Si or SiO_(x). The processing chamber is used toprocess one or more substrates. After removing the substrate from theprocessing chamber, the systems and methods supply a first gas selectedfrom a group consisting of silicon tetrachloride (SiCl₄), a hydrocarbon(C_(x)H_(y) where x and y are integers) and molecular chlorine (Cl₂),carbon tetrachloride (CCl₄), boron trichloride (BCl₃), and thionylchloride (SOCl₂). In some examples, an inert gas such as argon (Ar),helium (He), neon (N_(e)), or molecular nitrogen (N₂) may also besupplied to dilute the etch gas. Plasma is struck for a firstpredetermined period and then extinguished.

The first etching step selectively etches Sn relative to Si. A volatilecompound SnR_(x)O_(y)Cl_(z) is formed (where R=boron (B), carbon (C),sulfur (S), silicon (Si), etc.). After etching, the processing chamberis evacuated and then a second gas including fluorine species issupplied. In some examples, the second gas is selected from a groupconsisting of nitrogen trifluoride (NF₃), sulfur hexafluoride (SF₆), andcarbon tetrafluoride (CF₄). In some examples, an inert gas may also besupplied. Plasma is struck for a second predetermined period. The secondetch step selectively etches Si relative to Sn. The ordering of thefirst and second steps can be reversed.

In some examples, the first and second etch steps are not repeated orare repeated one or more times until the pre-coat layer is fully orsubstantially removed. After multiple cycles, metal contamination levelscan be reduced to less than 1e¹⁰/cm². Then, the surfaces of theprocessing chamber are pre-coated again and the substrate treatments areperformed again.

In some examples, the pressure in the processing chamber is adjusted todifferent pressures during the first step and the second step. In otherexamples, the pressure in the processing chamber is the same during thefirst step and the second step. Additional details are described furtherbelow.

Referring now to FIG. 1 , an example of a substrate processing system110 according to the present disclosure is shown. While the presentdisclosure will be described in the context of an inductively coupledplasma (ICP) processing chamber, other types of processing chambers canbe used.

The substrate processing system 110 includes a coil driving circuit 111.A pulsing circuit 114 may be used to pulse the RF power on and off orvary an amplitude or level of the RF power. The tuning circuit 113 maybe directly connected to one or more inductive coils 116. The tuningcircuit 113 tunes an output of the RF source 112 to a desired frequencyand/or a desired phase, matches an impedance of the coils 116 and splitspower between the coils 116. In some examples, the coil driving circuit111 is replaced by one of the drive circuits described further below inconjunction with controlling the RF bias.

In some examples, a plenum 120 may be arranged between the coils 116 anda dielectric window 124 to control the temperature of the dielectricwindow 124 with hot and/or cold air flow. The dielectric window 124 isarranged along one side of a processing chamber 128. The processingchamber 128 further comprises a substrate support (or pedestal) 132. Thesubstrate support 132 may include an electrostatic chuck (ESC), or amechanical chuck or other type of chuck. Process gas is supplied to theprocessing chamber 128 and plasma 140 is selectively generated inside ofthe processing chamber 128. The plasma 140 etches an exposed surface ofthe substrate 134. A drive circuit 152 may be used to provide an RF biasto an electrode in the substrate support 132 during operation.

A gas delivery system 156 may be used to supply a process gas such asetch gas, precursor gas, inert gas, etc. to the processing chamber 128.The gas delivery system 156 may include gas sources 157, a gas meteringsystem 158 such as valves and mass flow controllers, and a manifold 159.A gas delivery system 160 may be used to deliver gas 162 via a valve 61to the plenum 120. The gas may include cooling gas (air) that is used tocool the coils 116 and the dielectric window 124. A heater/cooler 164may be used to heat/cool the substrate support 132 to a predeterminedtemperature. An exhaust system 165 includes a valve 166 and pump 167 toremove reactants from the processing chamber 128 by purging orevacuation. The valve 166 and the pump 167 may be used to controlpressure in the processing chamber.

A pressure sensor 153 may be used to sense pressure inside of theprocessing chamber. A controller 154 may be used to control the etchingprocess. The controller 154 monitors system parameters such astemperature and pressure. The controller 154 controls delivery of thegas, striking, maintaining and extinguishing the plasma, removal ofreactants, supply of cooling gas, and so on. The controller 154 maycontrol the valve 166 and the pump 167 to vary pressure in theprocessing chamber. Additionally, as described below in detail, thecontroller 154 may control the cleaning process described herein.

Referring now to FIGS. 2A to 2D, a surface of a processing chamber 210is shown during cleaning using the cleaning systems and methodsdescribed herein. In FIG. 2A, a surface 220 of the processing chamber210 such as a chamber wall is shown. Prior to substrate treatment, thesurface 220 of the processing chamber 210 may be treated with a pre-coatlayer 224. In some examples, the pre-coat layer 224 includes silicon(Si) or silicon oxide (SiO_(x)), although other pre-coat layers 224 canbe used.

During substrate treatments such deposition or etching, residue 226contaminates the pre-coat layer 224. For example, SnOx may be depositedon the pre-coat layer. Steps are taken to remove the residue. In FIG.2B, a first gas is supplied to the processing chamber 210 and plasma isstruck for a first predetermined period and then extinguished. In someexamples, the first gas is selected from a group consisting of silicontetrachloride (SiCl₄), carbon tetrachloride (CCl₄), a hydrocarbon(C_(x)H_(y) where x and y are integers) and molecular chlorine (Cl₂),boron trichloride (BCl₃), and thionyl chloride (SOCl₂). The first gasetches tin (Sn) selectively relative to silicon (Si).

The processing chamber 210 is evacuated after the first predeterminedperiod. In FIG. 2C, a second gas including fluorine species is suppliedto the processing chamber 210 and plasma is struck for a secondpredetermined period and then extinguished. In some examples, the secondgas is selected from a group consisting of nitrogen trifluoride (NF₃),sulfur hexafluoride (SF₆), and carbon tetrafluoride (CF₄). The secondgas etches Si selectively relative to Sn. In this example, only onecycle is performed.

In FIG. 2D, the silicon or silicon oxide (SiO_(x)) pre-coat layer isapplied over the remnants of the prior pre-coat layer. For example, aprecursor gas such as silicon tetrachloride (SiCl₄), silane (SiH₄), orother silicon (Si) or silicon oxide (SiO_(x)) precursor gas is suppliedfor a predetermined period and plasma is struck. In some examples,molecular oxygen (O₂) gas is also supplied to the processing chamber.After the pre-coat layer is deposited, substrate treatment can becontinued. In some examples, the pre-coat layer is deposited usingplasma enhanced chemical vapor deposition (PECVD).

Referring now to FIGS. 3A to 3E, surfaces of a processing chamber 310are shown during cleaning using the cleaning systems and methodsdescribed herein. In FIG. 3A, a surface 320 of the processing chamber310 such as a chamber wall is shown. Prior to substrate treatment, apre-coat layer 324 may be deposited on the surface 320 of the processingchamber 310. In some examples, the pre-coat layer 324 includes siliconor silicon dioxide, although other types of pre-coat layers 324 can beused.

During substrate treatment (such as during deposition or etching),residue 326 such as Sn or SnO_(x) contaminates the pre-coat layer 324.To prevent process drift or defects, the contaminated pre-coat layer isetched. In FIG. 3B, a first gas is supplied to the processing chamber310 and plasma is struck for a first predetermined period. In someexamples, the first gas is selected from a group consisting of silicontetrachloride (SiCl₄), carbon tetrachloride (CCl₄), boron trichloride(BCl₃), a hydrocarbon (C_(x)H_(y) where x and y are integers) andmolecular chlorine (Cl₂), and thionyl chloride (SOCl₂). The plasmaetches tin (Sn) selectively relative to silicon (Si).

The processing chamber 310 is evacuated after the first predeterminedperiod. In FIG. 3C, a second gas including fluorine species is suppliedto the processing chamber 310 and plasma is struck for a secondpredetermined period. In some examples, the second gas is selected froma group consisting of nitrogen trifluoride (NF₃), sulfur hexafluoride(SF₆), and carbon tetrafluoride (CF₄). The plasma etches Si selectivelyrelative to Sn. The steps shown in FIGS. 3B and 3C can be repeated oneor more times. In some examples, the steps are repeated until thepre-coat layer and residuals are removed from the surface.

In FIG. 3D, the surface of the processing chamber is shown after removalof the pre-coat layer and residuals. In FIG. 3E, the silicon oxide(SiOx) pre-coat layer is applied again and the processing chamber isready to perform substrate treatment again.

Referring now to FIG. 4 , a method 410 for cleaning surfaces of thesubstrate processing system is shown. Prior to substrate treatments, apre-coat layer is applied to surfaces of the processing chamber. At 414,one or more substrate treatments are performed on substrate(s). Duringthe substrate treatments, residue forms on surfaces of the processingchamber. In some examples, the substrate treatment includes deposition,etching, cleaning or other treatment.

At 418, the method determines whether the chamber is to be cleaned.Chamber cleaning can be performed periodically such as every P processcycle (where P is an integer greater than zero), on an event basis (suchas when an event occurs), or using other criteria. If chamber cleaningis to be performed at 418, the substrate is removed from the processingchamber at 422 (if needed). At 426, the chamber pressure is set to afirst pressure value in a first pressure range. At 430, the first gas(or the second gas) is supplied to the processing chamber and plasma isstruck for a first predetermined period. In some examples, the first gasselected from a group consisting of silicon tetrachloride (SiCl₄),carbon tetrachloride (CCl₄), boron trichloride (BCl₃), a hydrocarbon(C_(x)H_(y) where x and y are integers) and molecular chlorine (Cl₂),and thionyl chloride (SOCl₂). In some examples, the second gas isselected from a group consisting of nitrogen trifluoride (NF₃), sulfurhexafluoride (SF₆), and carbon tetrafluoride (CF₄).

At 434, the chamber pressure is set to a second pressure value in asecond pressure range. At 438, the second gas (or the first gas) issupplied to the processing chamber and plasma is struck for a secondpredetermined period. At 442, the process may be repeated one or moretimes. After the one or more cycles are complete, the surfaces of theprocessing chamber are pre-coated and then additional substratetreatments can be performed in the processing chamber.

In some examples, the chamber pressure during the chlorine species etchis maintained in a predetermined range from 1 to 30 mT (milliTorr). Inother examples, the chamber pressure during the chlorine species etch ismaintained in a predetermined range from 4 to 12 mT. In other examples,the chamber pressure during the chlorine species etch is maintained in apredetermined range from 7 to 9 mT. In other examples, the chamberpressure during the chlorine species etch is maintained at 8 mT.

In some examples, the chamber pressure during the fluorine species etchis maintained in a predetermined range from 30 to 150 mT. In otherexamples, the chamber pressure during the fluorine species etch ismaintained in a predetermined range from 50 to 80 mT. In other examples,the chamber pressure during the fluorine species etch is maintained in apredetermined range from 60 to 70 mT. In other examples, the chamberpressure during the fluorine species etch is maintained at 65 mT.

In some examples, the etch periods for the chlorine and fluorine etchspecies are in a range from 1 to 30 seconds. In some examples, the etchperiods for the chlorine and fluorine etch species are in a range from 1to 10 seconds. In some examples, the etch periods for the chlorine andfluorine etch species are in a range from 3 to 7 seconds. In someexamples, the etch periods for the chlorine and fluorine etch speciesare 5 seconds. As can be appreciated, the etch periods will varydepending upon the processing chamber, concentration of etch gas andtype of plasma that is used. Additionally, the etch periods will alsovary depending upon the plasma power. Higher plasma will increase theetch rate and decrease the etch periods.

In some examples, the plasma power during the chlorine and fluorineetching is in a range from 100 W to 3000 W. In some examples, the plasmapower during the chlorine and fluorine etching is in a range from 500 Wto 2500 W. In some examples, the plasma power during the chlorine andfluorine etching is in a range from 1300 W to 2300 W. In some examples,the plasma power during the chlorine and fluorine etching is 1800 W. Insome examples, the plasma power during the pre-coat is in a range from500 W to 2000 W. In some examples, the plasma power during the pre-coatis in a range from 500 W to 1500 W. In some examples, the plasma powerduring the pre-coat is 1000 W.

In some examples, 100 to 300 standard cubic centimeters (sccm) of gasincluding chlorine species or fluorine species are supplied during therespective etching steps. In some examples, 200 sccm of gas includingchlorine species or fluorine species are supplied during the respectiveetching steps.

The foregoing description is merely illustrative in nature and is in noway intended to limit the disclosure, its application, or uses. Thebroad teachings of the disclosure can be implemented in a variety offorms. Therefore, while this disclosure includes particular examples,the true scope of the disclosure should not be so limited since othermodifications will become apparent upon a study of the drawings, thespecification, and the following claims. It should be understood thatone or more steps within a method may be executed in different order (orconcurrently) without altering the principles of the present disclosure.Further, although each of the embodiments is described above as havingcertain features, any one or more of those features described withrespect to any embodiment of the disclosure can be implemented in and/orcombined with features of any of the other embodiments, even if thatcombination is not explicitly described. In other words, the describedembodiments are not mutually exclusive, and permutations of one or moreembodiments with one another remain within the scope of this disclosure.

Spatial and functional relationships between elements (for example,between modules, circuit elements, semiconductor layers, etc.) aredescribed using various terms, including “connected,” “engaged,”“coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and“disposed.” Unless explicitly described as being “direct,” when arelationship between first and second elements is described in the abovedisclosure, that relationship can be a direct relationship where noother intervening elements are present between the first and secondelements, but can also be an indirect relationship where one or moreintervening elements are present (either spatially or functionally)between the first and second elements. As used herein, the phrase atleast one of A, B, and C should be construed to mean a logical (A OR BOR C), using a non-exclusive logical OR, and should not be construed tomean “at least one of A, at least one of B, and at least one of C.”

In some implementations, a controller is part of a system, which may bepart of the above-described examples. Such systems can comprisesemiconductor processing equipment, including a processing tool ortools, chamber or chambers, a platform or platforms for processing,and/or specific processing components (a wafer pedestal, a gas flowsystem, etc.). These systems may be integrated with electronics forcontrolling their operation before, during, and after processing of asemiconductor wafer or substrate. The electronics may be referred to asthe “controller,” which may control various components or subparts ofthe system or systems. The controller, depending on the processingrequirements and/or the type of system, may be programmed to control anyof the processes disclosed herein, including the delivery of processinggases, temperature settings (e.g., heating and/or cooling), pressuresettings, vacuum settings, power settings, radio frequency (RF)generator settings, RF matching circuit settings, frequency settings,flow rate settings, fluid delivery settings, positional and operationsettings, wafer transfers into and out of a tool and other transfertools and/or load locks connected to or interfaced with a specificsystem.

Broadly speaking, the controller may be defined as electronics havingvarious integrated circuits, logic, memory, and/or software that receiveinstructions, issue instructions, control operation, enable cleaningoperations, enable endpoint measurements, and the like. The integratedcircuits may include chips in the form of firmware that store programinstructions, digital signal processors (DSPs), chips defined asapplication specific integrated circuits (ASICs), and/or one or moremicroprocessors, or microcontrollers that execute program instructions(e.g., software). Program instructions may be instructions communicatedto the controller in the form of various individual settings (or programfiles), defining operational parameters for carrying out a particularprocess on or for a semiconductor wafer or to a system. The operationalparameters may, in some embodiments, be part of a recipe defined byprocess engineers to accomplish one or more processing steps during thefabrication of one or more layers, materials, metals, oxides, silicon,silicon dioxide, surfaces, circuits, and/or dies of a wafer.

The controller, in some implementations, may be a part of or coupled toa computer that is integrated with the system, coupled to the system,otherwise networked to the system, or a combination thereof. Forexample, the controller may be in the “cloud” or all or a part of a fabhost computer system, which can allow for remote access of the waferprocessing. The computer may enable remote access to the system tomonitor current progress of fabrication operations, examine a history ofpast fabrication operations, examine trends or performance metrics froma plurality of fabrication operations, to change parameters of currentprocessing, to set processing steps to follow a current processing, orto start a new process. In some examples, a remote computer (e.g. aserver) can provide process recipes to a system over a network, whichmay include a local network or the Internet. The remote computer mayinclude a user interface that enables entry or programming of parametersand/or settings, which are then communicated to the system from theremote computer. In some examples, the controller receives instructionsin the form of data, which specify parameters for each of the processingsteps to be performed during one or more operations. It should beunderstood that the parameters may be specific to the type of process tobe performed and the type of tool that the controller is configured tointerface with or control. Thus as described above, the controller maybe distributed, such as by comprising one or more discrete controllersthat are networked together and working towards a common purpose, suchas the processes and controls described herein. An example of adistributed controller for such purposes would be one or more integratedcircuits on a chamber in communication with one or more integratedcircuits located remotely (such as at the platform level or as part of aremote computer) that combine to control a process on the chamber.

Without limitation, example systems may include a plasma etch chamber ormodule, a deposition chamber or module, a spin-rinse chamber or module,a metal plating chamber or module, a clean chamber or module, a beveledge etch chamber or module, a physical vapor deposition (PVD) chamberor module, a chemical vapor deposition (CVD) chamber or module, anatomic layer deposition (ALD) chamber or module, an atomic layer etch(ALE) chamber or module, an ion implantation chamber or module, a trackchamber or module, and any other semiconductor processing systems thatmay be associated or used in the fabrication and/or manufacturing ofsemiconductor wafers.

As noted above, depending on the process step or steps to be performedby the tool, the controller might communicate with one or more of othertool circuits or modules, other tool components, cluster tools, othertool interfaces, adjacent tools, neighboring tools, tools locatedthroughout a factory, a main computer, another controller, or tools usedin material transport that bring containers of wafers to and from toollocations and/or load ports in a semiconductor manufacturing factory.

What is claimed is:
 1. A method for cleaning surfaces of a substrateprocessing chamber, comprising: a) supplying a first gas selected from agroup consisting of silicon tetrachloride (SiCl₄), carbon tetrachloride(CCl₄), a hydrocarbon (C_(x)H_(y) where x and y are integers) andmolecular chlorine (Cl₂), boron trichloride (BCl₃), and thionyl chloride(SOCl₂), wherein the first gas is configured to selectively etch tin(Sn) relative to silicon (Si); b) striking plasma in the substrateprocessing chamber with the first gas to selectively etch Sn relative toSi from the surfaces of the substrate processing chamber; c)extinguishing the plasma struck in b) and evacuating the substrateprocessing chamber; d) supplying a second gas including fluorinespecies, wherein the second gas is configured to selectively etch Sirelative to Sn; e) subsequent to d), striking plasma in the substrateprocessing chamber with the second gas to selectively etch Si relativeto Sn from the surfaces of the substrate processing chamber; and f)extinguishing the plasma struck in e) and evacuating the substrateprocessing chamber.
 2. The method of claim 1, further comprising: g)repeating a) to c) and d) to f) N times, where N is an integer greaterthan zero.
 3. The method of claim 1, wherein the second gas is selectedfrom a group consisting of nitrogen trifluoride (NF₃), sulfurhexafluoride (SF₆), and carbon tetrafluoride (CF₄).
 4. The method ofclaim 2, wherein a) to g) are performed without a substrate located on asubstrate support in the substrate processing chamber.
 5. The method ofclaim 2, further comprising pre-coating the surfaces of the substrateprocessing chamber with a material selected from a group consisting ofsilicon (Si) and silicon oxide (SiO_(x)) after g).
 6. The method ofclaim 2, wherein a) to c) are performed after d) to f) during each ofthe N times.
 7. The method of claim 2, wherein a) to c) are performedbefore d) to f) during each of the N times.
 8. The method of claim 2,further comprising: prior to performing a) to g): pre-coating a surfaceof the substrate processing chamber with a material selected from agroup consisting of silicon (Si) and silicon oxide (SiO_(x)); andperforming a substrate treatment; and after g): pre-coating the surfaceof the substrate processing chamber with a material selected from agroup consisting of silicon (Si) and silicon oxide (SiO_(x)); andperforming a substrate treatment.
 9. The method of claim 8, wherein thesubstrate treatment comprises etching.
 10. The method of claim 9,wherein the substrate includes tin (Sn) and wherein Sn contamination isless than 1e10/cm2 after g).
 11. The method of claim 1, furthercomprising: controlling a first pressure in the substrate processingchamber during b) within a first pressure range; and controlling asecond pressure in the substrate processing chamber during e) within asecond pressure range, wherein the first pressure range is less than thesecond pressure range.
 12. The method of claim 11, wherein the firstpressure range is from 1 to 30 mT and wherein the second pressure rangeis from 30 to 150 mT.
 13. A substrate processing system for treating asubstrate, comprising: a processing chamber comprising chamber walls anda substrate support; a gas delivery system configured to selectivelydeliver gases to the processing chamber, the gas delivery systemcomprising a first gas source comprising a first gas and a second gassource comprising a second gas, wherein the first gas is selected from agroup consisting of silicon tetrachloride (SiCl₄), carbon tetrachloride(CCl₄), a hydrocarbon (C_(x)H_(y) where x and y are integers) andmolecular chlorine (Cl₂), boron trichloride (BCl₃), and thionyl chloride(SOCl₂), wherein the first gas is configured to selectively etch tin(Sn) relative to silicon (Si), and wherein the second gas includes afluorine species and is configured to selectively etch Si relative toSn; a plasma generator configured to selectively generate plasma in theprocessing chamber; and a controller programed to perform a processingchamber clean comprising: a) supplying the first gas; b) striking plasmain the processing chamber with the first gas to selectively etch Snrelative to Si from surfaces of the processing chamber; c) extinguishingthe plasma struck in b) and evacuating the processing chamber; d)supplying the second gas; e) subsequent to d), striking plasma in theprocessing chamber with the second gas to selectively etch Si relativeto Sn from the surfaces of the processing chamber; and f) extinguishingthe plasma struck in e) and evacuate the processing chamber.
 14. Thesubstrate processing system of claim 13, wherein the controller isfurther configured to control the gas delivery system and the plasmagenerator to: g) repeat a) to c) and d) to f) N times, where N is aninteger greater than zero.
 15. The substrate processing system of claim13, wherein the second gas is selected from a group consisting ofnitrogen trifluoride (NF₃), sulfur hexafluoride (SF₆), and carbontetrafluoride (CF₄).
 16. The substrate processing system of claim 14,wherein the controller is configured to control a robot to remove thesubstrate from the substrate support prior to performing a) to g). 17.The substrate processing system of claim 14, wherein the controller isconfigured to control the gas delivery system and the plasma generatorto pre-coat the surfaces of the processing chamber with a materialselected from a group consisting of silicon (Si) and silicon oxide(SiO_(x)) after g).
 18. The substrate processing system of claim 14,wherein the controller is configured to control the gas delivery systemand the plasma generator to perform a) to c) after d) to f) during eachof the N times.
 19. The substrate processing system of claim 14, whereinthe controller is configured to control the gas delivery system and theplasma generator to perform a) to c) before d) to f) during each of theN times.
 20. The substrate processing system of claim 14, wherein thecontroller is configured to control the gas delivery system and theplasma generator to: prior to performing a) to g): pre-coat a surfacesof the processing chamber with a material selected from a groupconsisting of silicon (Si) and silicon oxide (SiO_(x)); and perform asubstrate treatment; and after g): pre-coat the surface of theprocessing chamber with a material selected from a group consisting ofsilicon (Si) and silicon oxide (SiO_(x)); and perform a substratetreatment.
 21. The substrate processing system of claim 20, wherein thesubstrate treatment comprises etching.
 22. The substrate processingsystem of claim 21, wherein the substrate includes tin (Sn) and whereinSn contamination is less than 5e9/cm2 after g).
 23. The substrateprocessing system of claim 13, wherein the controller is configured tocontrol the gas delivery system and the plasma generator to: control afirst pressure in the processing chamber during b) to a first pressurerange; and control a second pressure in the processing chamber during e)to a second pressure range, wherein the first pressure range is lessthan the second pressure range.
 24. The substrate processing system ofclaim 23, wherein the first pressure range is from 1 to 30 mT andwherein the second pressure range is from 30 to 100 mT.